AD replication time?

Hi guys,

Could any of you tell me where I can see the replication time for our AD between sites or across a WAN? Somebody from a hosting solutions provider told us that ours is set between 0 to 30 days on our LAN? I was baffled.

Do any of you know where I can find this setting whereby I can reduce the amount of time it takes to replicate AD from one site to another?